Mag length ammo and jump to lands, what is typical?



  • Finally took the time to use my Hornaday gauge set.
    Colt 6700 HBAR NATO Chamber 1/9 twist
    I had some 68 HPBT loaded to fit the magazine and wanted to see how far it was off the lands.
    First loaded BTO

    IMG_20170302_112942_zpsakd8vhm4.jpg

    Then max possible BTO

    IMG_20170302_112838_zpsqxsr9zl2.jpg

    Is 0.1015 normal?
    I think I may try a single loading sled and see if 1.95" BTO is much better.

    Other measurements
    Sierra 69 TMK was 1.94" max BTO
    A 52 HPBT was 2.0025 and was less than a bullet diameter down the neck.
    That and a 52 AMax are pointless to load beyond magazine length.
    Factory LC14 XM193 was 1.9125 BTO

    IMG_20170302_120936_edit_zpsx0jttzma.jpg



  • @hypo said:

    Is 0.1015 normal?

    It's normal for factory rifles, if there is such a thing as "normal" for factory rifles.



  • Looks like this is going to be my offhand practice, self defense, short range hunting upper.

    1 MOA with magazine length ammo might be wishful thinking.



  • Why do you say that? I have seen 1/3-1/2 MOA pretty regular out of capable rifles with long freebore.

    Jump doesn't automatically mean poor performance.



  • Inexperienced is the honest answer.
    That is why I ask here.
    Experience and experimental evidence will be the touchstone.
    Going to load some up this weekend.
    Need to get out to a longer range.
    I have 600 bullets on hand to load.
    200 52 HPBT
    100 52 Amax
    200 68 HPBT
    100 69 TMK

    Might get some 75 HPBT when the stores open in the morning on my way home from work.
    Break time over.
    235 miles back to Atlanta now.



  • SMK's are historically the most jump-tolerant bullets I've used.


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